diff --git a/urjtag/ChangeLog b/urjtag/ChangeLog
index 3e78b8ff..75c66bb0 100644
--- a/urjtag/ChangeLog
+++ b/urjtag/ChangeLog
@@ -1,3 +1,11 @@
+2010-02-10  Jie Zhang  <jie.zhang@analog.com>
+
+  * src/tap/usbconn/libftdx.h (URJ_USBCONN_FTDI_MAXRECV): Define
+    to be (63 * 64) if HAVE_LIBFTDI_ASYNC_MODE defined.
+  * src/tap/usbconn/libftdi.c (usbconn_ftdi_flush): Use async
+    mode libftdi if HAVE_LIBFTDI_ASYNC_MODE defined.
+  * configure.ac: Check libusb-1.0 and libftdi async mode.
+
 2010-02-09  Mike Frysinger  <vapier@gentoo.org>
 
   * src/urjtag.pc.in: Include -Llibdir in default output and let pkg-config
diff --git a/urjtag/configure.ac b/urjtag/configure.ac
index e1271156..1b3ca4d5 100644
--- a/urjtag/configure.ac
+++ b/urjtag/configure.ac
@@ -150,7 +150,7 @@ AC_ARG_WITH([libusb],
     [with_libusb=check])
 
 HAVELIBUSB=no
-AS_IF([test "x$with_libusb" != xno], [
+AS_IF([test "x$with_libusb" != xno -a "x$with_libusb" != x1.0], [
   save_LIBS=$LIBS
   save_CPPFLAGS=$CPPFLAGS
   PKG_CHECK_MODULES(LIBUSB, libusb, [:;], [dnl
@@ -161,7 +161,7 @@ AS_IF([test "x$with_libusb" != xno], [
         LIBUSB_CFLAGS="-I$with_libusb/include"
         ;;
       *)
-        LIBUSB_LIBS="-Lwith_libusb -lusb"
+        LIBUSB_LIBS="-L$with_libusb -lusb"
         LIBUSB_CFLAGS="-I$with_libusb"
         ;;
       esac
@@ -179,7 +179,11 @@ AS_IF([test "x$with_libusb" != xno], [
     AC_DEFINE(HAVE_LIBUSB, 1, [Define if you have libusb])
     HAVELIBUSB=yes
   ],[
-    AC_MSG_WARN([*** libusb not detected. No support for USB JTAG cables via libusb.])
+    AS_IF([test "x$with_libusb" = x0.1], [
+      AC_MSG_ERROR([*** libusb-0.1 not detected.])
+    ],[
+      AC_MSG_WARN([*** libusb not detected. No support for USB JTAG cables via libusb.])
+    ])
     LIBS=$save_LIBS
     CPPFLAGS=$save_CPPFLAGS
   ])
@@ -187,6 +191,35 @@ AS_IF([test "x$with_libusb" != xno], [
 AM_CONDITIONAL(HAVE_LIBUSB, [test "x$HAVELIBUSB" = "xyes"])
 
 
+dnl check for libusb-1.0
+
+HAVELIBUSB1=no
+AS_IF([test "x$with_libusb" != xno -a "x$with_libusb" != x0.1 -a "x$HAVELIBUSB" != "xyes"], [
+  save_LIBS=$LIBS
+  save_CPPFLAGS=$CPPFLAGS
+  PKG_CHECK_MODULES(LIBUSB1, libusb-1.0, have_libusb1=yes, have_libusb1=no)
+  AS_IF([test "$have_libusb1" = "yes"],[
+    LIBUSB_CFLAGS="$CFLAGS $LIBUSB1_CFLAGS"
+    LIBUSB_LIBS="$USB_LIBS $LIBUSB1_LIBS"
+  ],)
+  LIBS="$LIBS $LIBUSB1_LIBS"
+  CPPFLAGS="$CPPFLAGS $LIBUSB1_CFLAGS"
+  AC_CHECK_FUNC([libusb_get_device_list], [
+    AC_DEFINE(HAVE_LIBUSB1, 1, [Define if you have libusb-1.0])
+    HAVELIBUSB1=yes
+  ],[
+    AS_IF([test "x$with_libusb" = x1.0], [
+      AC_MSG_ERROR([*** libusb-1.0 not detected.])
+    ],[
+      AC_MSG_WARN([*** libusb-1.0 not detected. No support for async mode for FTDI cables.])
+    ])
+    LIBS=$save_LIBS
+    CPPFLAGS=$save_CPPFLAGS
+  ])
+],)
+AM_CONDITIONAL(HAVE_LIBUSB1, [test "x$HAVELIBUSB1" = "xyes"])
+
+
 dnl Use FTDI library?
 
 AC_ARG_WITH([libftdi],
@@ -220,8 +253,20 @@ AS_IF([test "x$with_libftdi" != xno], [
     LIBS=$save_LIBS
     CPPFLAGS=$save_CPPFLAGS
   ])
+  AC_CHECK_FUNC([ftdi_read_data_submit], [
+    AS_IF([test "x$HAVELIBUSB" = "xyes"], [
+      AC_MSG_ERROR([this libftdi cannot be used with libusb-0.1, libusb-1.0 is needed])
+    ],)
+    AC_DEFINE(HAVE_LIBFTDI_ASYNC_MODE, 1, [Define if libftdi support async mode])
+    HAVELIBFTDI_ASYNCMODE=yes
+  ], [
+    AS_IF([test "x$HAVELIBUSB1" = "xyes"], [
+      AC_MSG_ERROR([this libftdi cannot be used with libusb-1.0, libusb-0.1 is needed])
+    ],)
+  ])
 ],)
 AM_CONDITIONAL(HAVE_LIBFTDI, [test "x$HAVELIBFTDI" = "xyes"])
+AM_CONDITIONAL(HAVE_LIBFTDI_ASYNC_MODE, [test "x$HAVELIBFTDI_ASYNCMODE" = "xyes"])
 
 
 dnl Use FTDI ftd2xx library?
@@ -682,6 +727,20 @@ AC_OUTPUT
 dnl
 dnl Configuration summary
 dnl
+AS_IF([test "x$HAVELIBUSB" = "xyes"], [
+  FLAG_HAVELIBUSB=0.1
+], [
+  AS_IF([test "x$HAVELIBUSB1" = "xyes"], [
+    FLAG_HAVELIBUSB=1.0
+  ],[
+    FLAG_HAVELIBUSB=no
+  ])
+])
+AS_IF([test "x$HAVELIBFTDI_ASYNCMODE" = "xyes"], [
+  FLAG_HAVELIBFTDI_ASYNCMODE="(have async mode)"
+],[
+  FLAG_HAVELIBFTDI_ASYNCMODE="(no async mode)"
+])
 AC_DEFUN([MAKE_YESNO_VAR],[dnl
   AS_IF([test ${$1:-$2} != $2], [dnl
      FLAG_$1=yes
@@ -690,7 +749,6 @@ AC_DEFUN([MAKE_YESNO_VAR],[dnl
   ])
 ])
 MAKE_YESNO_VAR([HAVELIBFTDI], [no])
-MAKE_YESNO_VAR([HAVELIBUSB], [no])
 MAKE_YESNO_VAR([HAVELIBFTD2XX], [no])
 MAKE_YESNO_VAR([HAVE_INPOUTXX], [no])
 MAKE_YESNO_VAR([svf], [false])
@@ -700,7 +758,7 @@ AC_MSG_NOTICE([
 jtag is now configured for
 
   Detected libusb      : $FLAG_HAVELIBUSB
-  Detected libftdi     : $FLAG_HAVELIBFTDI
+  Detected libftdi     : $FLAG_HAVELIBFTDI $FLAG_HAVELIBFTDI_ASYNCMODE
   Detected libftd2xx   : $FLAG_HAVELIBFTD2XX
   Detected inpout32    : $FLAG_HAVE_INPOUTXX
   Build SVF player     : $FLAG_svf
diff --git a/urjtag/src/tap/usbconn/libftdi.c b/urjtag/src/tap/usbconn/libftdi.c
index 34457d04..3e1f9b01 100644
--- a/urjtag/src/tap/usbconn/libftdi.c
+++ b/urjtag/src/tap/usbconn/libftdi.c
@@ -68,6 +68,9 @@ usbconn_ftdi_flush (ftdi_param_t *p)
 {
     int xferred;
     int recvd = 0;
+#ifdef HAVE_LIBFTDI_ASYNC_MODE
+    struct ftdi_transfer_control *tc = NULL;
+#endif
 
     if (!p->fc)
         return -1;
@@ -75,6 +78,7 @@ usbconn_ftdi_flush (ftdi_param_t *p)
     if (p->send_buffered == 0)
         return 0;
 
+#ifndef HAVE_LIBFTDI_ASYNC_MODE
     if ((xferred = ftdi_write_data (p->fc, p->send_buf, p->send_buffered)) < 0)
         urj_error_set (URJ_ERROR_FTD, _("ftdi_write_data() failed: %s"),
                        ftdi_get_error_string (p->fc));
@@ -87,6 +91,7 @@ usbconn_ftdi_flush (ftdi_param_t *p)
     }
 
     p->send_buffered = 0;
+#endif
 
     /* now read all scheduled receive bytes */
     if (p->to_recv)
@@ -106,6 +111,33 @@ usbconn_ftdi_flush (ftdi_param_t *p)
             return -1;
         }
 
+#ifdef HAVE_LIBFTDI_ASYNC_MODE
+        if ((tc = ftdi_read_data_submit (p->fc,
+                                         &(p->recv_buf[p->recv_write_idx]),
+                                         p->to_recv)) == NULL)
+            urj_error_set (URJ_ERROR_FTD,
+                           _("Error from ftdi_read_data_submit(): %s"),
+                           ftdi_get_error_string (p->fc));
+    }
+
+    if ((xferred = ftdi_write_data (p->fc, p->send_buf, p->send_buffered)) < 0)
+    {
+        urj_error_set (URJ_ERROR_FTD, ftdi_get_error_string (p->fc));
+        return -1;
+    }
+
+    if (xferred < p->send_buffered)
+    {
+        urj_error_set (URJ_ERROR_FTD, _("Written fewer bytes than requested."));
+        return -1;
+    }
+
+    p->send_buffered = 0;
+
+    if (p->to_recv)
+    {
+        recvd = ftdi_transfer_data_done (tc);
+#else
         while (recvd == 0)
             if ((recvd = ftdi_read_data (p->fc,
                                          &(p->recv_buf[p->recv_write_idx]),
@@ -113,6 +145,7 @@ usbconn_ftdi_flush (ftdi_param_t *p)
                 urj_error_set (URJ_ERROR_FTD,
                                _("Error from ftdi_read_data(): %s"),
                                ftdi_get_error_string (p->fc));
+#endif
 
         if (recvd < p->to_recv)
             urj_log (URJ_LOG_LEVEL_NORMAL,
diff --git a/urjtag/src/tap/usbconn/libftdx.h b/urjtag/src/tap/usbconn/libftdx.h
index f84e5cf9..7003cebc 100644
--- a/urjtag/src/tap/usbconn/libftdx.h
+++ b/urjtag/src/tap/usbconn/libftdx.h
@@ -30,7 +30,11 @@
    Larger values might speed up comm, but there's an upper limit
    when too many bytes are sent and the underlying libftdi or libftd2xx
    don't fetch the returned data in time -> deadlock */
+#ifdef HAVE_LIBFTDI_ASYNC_MODE
+#define URJ_USBCONN_FTDI_MAXRECV   (63 * 64)
+#else
 #define URJ_USBCONN_FTDI_MAXRECV   ( 4 * 64)
+#endif
 #define URJ_USBCONN_FTD2XX_MAXRECV (63 * 64)
 #define URJ_USBCONN_FTDX_MAXRECV   (URJ_USBCONN_FTD2XX_MAXRECV < URJ_USBCONN_FTDI_MAXRECV ? URJ_USBCONN_FTD2XX_MAXRECV : URJ_USBCONN_FTDI_MAXRECV)